AB1253 FEBUXOSTAT DOSE ADJUSTMENT ACCORDING TO RENAL FUNCTION TO ATTAIN TARGET SERUM URATE LEVEL: A RETROSPECTIVE COHORT STUDY
Authors: Y. E. Kim, S. M. Ahn, J. S. Oh, Y. G. Kim, C. K. Lee, B. Yoo, S. Hong
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Current guideline for gout recommends the use of allopurinol or febuxostat in moderate-to-severe chronic kidney disease (CKD). However, the appropriate febuxostat dosage required to attain the target serum urate (SU) level remains unclear, especially in patients with renal impairment. <h3>Objectives</h3> We aim to investigate the different febuxostat dosages stratified by renal function to achieve the target SU level. <h3>Methods</h3> We collected the clinical and laboratory information of patients using the Clinical Research Data Warehouse system of Asan Medical Center, Seoul, South Korea. Of the 3153 patients with gout and a prescription for febuxostat at a tertiary-care referral center, 731 with initial SU levels &gt;6 mg/dL were collected and categorized, according to their eGFR levels at febuxostat therapy initiation, into three groups based on CKD stage: 1, 2–3, and 4–5. We defined the cumulative febuxostat as the total dose of febuxostat used from the initiation of febuxostat to the moment patient reached the SU target (SU&lt;6 mg/dL). <h3>Results</h3> This cohort of 731 gout patients, with a median age of 52 (IQR, 41-63) years, included 64 (8.8%) women. Compared with the other groups, in the CKD 4–5 group, the mean SU value at febuxostat initiation was significantly higher (9.6 [SD, 3.1] mg/dL; CKD 2–3, 8.6 [SD, 1.6] mg/dL; CKD 1, 8.8 [SD, 1.8] mg/dL; p&lt;0.001) and significantly fewer patients achieved the SU target during the follow-up period, median 31 (IQR, 13-55) months. In the subgroup analysis of patients who achieved target SU levels, the cumulative dose of febuxostat was significantly lower in CKD 4-5 patients compared to those with other groups (CKD 4–5, 5.9 (IQR, 2.5–12.0) g; CKD 2–3, 7.1 (IQR, 3.5–15.7) g; CKD 1, 7.0 (IQR, 2.7–20.1) g; p=0.010 for CKD 4–5 and CKD 1, p=0.006 for CKD 4–5 and CKD 2–3). The average febuxostat dose used during 4 months to reach the SU target was 50.0 (IQR, 21.0–101.0) mg in the CKD 4-5 group, which was significantly lower than in other groups (CKD 2–3, 59.3 (IQR, 29.4–130.7) mg; CKD 1, 58.5 (IQR, 22.7–167.8) mg; p=0.006 for CKD 4–5 and CKD 1, p=0.003 for CKD 4–5 and CKD 2–3). In addition, when we examined the clinical factors associated with the required dose of febuxostat to achieve SU target, CKD 4-5 group showed a significant negative correlation with cumulative febuxostat dosage to reach target SU compared with CKD 1 (rho -2.334, p=0.02). <h3>Conclusion</h3> The febuxostat dose required to reach the target SU level was significantly lower in patients with markedly decreased renal function (CKD stage 4–5). <h3>References</h3> [1]Tan VS et al. The 3-Year Incidence of Gout in Elderly Patients with CKD. Clinical Journal of the American Society of Nephrology. 2017; 12(4):577-584. [2]Stamp LK et al. A randomised controlled trial of the efficacy and safety of allopurinol dose escalation to achieve target serum urate in people with gout. Annals of the Rheumatic Diseases. 2017; 76(9):1522-1528. [3]Ahn E et al. Comparison of Efficacy and Safety of Febuxostat in Gout Patients with Chronic Kidney Disease Stage 3 and Stage 4/5. Journal of Rheumatic Diseases. 2019; 26(2):118. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.